Mining chain bit holder and bit



June 29, 1943. F. L. FULKE 2,322,929

mums 0mm azw uommn AND an Original Filed July 18, 1938 INVENTOR.

JI'E/Li L Ill/168,

ATTORNEYS.

Patented June 29, 1943 2,822,929 CHAIN BIT HOLDER AND. BIT

Frank L. Fulke, Terre Haute, lnd assignor to Frank Prox Company, 'Inc., Tom Hante, 'InrL,

a corporation. Indiana Continuation of application Serial No. 219,709, July 18, 1938. This application November 9. 1940, Serial No. 365,905

17 Claims. (Cl. 262-83) The present application is a continuation oi my application Serial No. 219,709, filed July 18, 1938, being identical therewith in disclosure; and. this application is, as was my said application Serial No. 219,709 a continuation in part of my application Serial No. 23,017, filed May 23, 1935, for Mining machine cutter chainandmethod oi making elements thereof, now Patent No 2,158,725, issued May 2, i939, and my application Serial No. 23,592, filed May 27, 1935, for Mining machine and elements thereof, now Patent No.

2,158,726, issued May 2, 1939. This application is primarily directed toward the particular cutter bit disclosed in said patents and holding means therefor constituting an improvement over the holding means disclosed in the said patents.

An object of the present invention is to provide a bit for mining machine cutter chains which shall be extremely inexpensive, as compared to previously known bits, but which shall be of such character as to provide improved emciency, improved tacility or handling and changing, and to provide two alternatively usable cutter points. A further object of the invention is to provide a workable holder for such bits, employing only three pieces, yet providing for easy replacement oi the wearable piece that holds the bit.

Through experience with small multiple pointed bits I have found that serious problems are involved in sripp nssuch a small piece in cutting position, due to the iact that when cutting in hard impurities, any outward extension or proiection from the surface or the blocks is severely abraded faway b hard material not removed by the bit 'pointslor sides closely I am Iaware'ot structures in which rear surfaces or such small hits are supported formed ntegrally with the blook with a clamp piece screw ahead of the bit to engage and lock'it, thus constituting a three piece holder.

However such construction requires replacement of the expensive block itself when the bit supporting portion becomes mutilated by coring. I obviate this by providing a replaceable tool post projecting outward from the link to support the rear surface of the bit, said tool post being provided with a head which cooperates with an inclined flat surface on the bit block to clamp the bit in cutting position.

Further and more particular objects oi the invention will appear as the description proceeds.

To the accomplishment of the above and related objects, my invention may be embodied in the form illustrated in the accompanying drawing, attention being called to the iact,.however,

that the drawing is illustrative only, and that change may be made in the specific construction I illustrated and described, so long as the scope oi the appended claims is not violated.

Figi sis-a bottom plan view ot a mining machine chain link formed to accommodate my novel bit holding means, and showing such means in to clamp my novel bit in place on the link or block;

Fig. 2 is a fragmentary longitudinal section taken upon a plane parallel to the plane or Fig.1;

Fig.2, is a side elevation of the bit of the present invention;

1"ig. 4 is a rear elevation thereof;

Pig. 5 isan end'view thereoi; and

P18. 6 is a reduced end elevation of theorgantnation of Fig. l.

Referring more particularly to the draw. it

"will be seen that 1 have illustrated a mining machine chain link indicated generally by the reference numeral 2|. Said link comprises, as usual, a head 2|, and is formed with a bore from the outermost surface of the head 2| entirely through the link, said bore in the illustrated embodiment consisting-o! an enlarged portion 22 and a smaller portion 22.

The bore is formed, at its outermost portion,

; to provide an outwardly and forwardly sloping ilat suriace u for a purpose later to be described. The link block is preferably formed with a second .bore'II opening from the bore 22, at a point adjacent the shoulder formed between them!- tions 22 and 22. through that wall or the block directiy'inasocket' which, in the working position or the block, is directed downwardly.

The bit of the present application is indicated generally by the reference numeral 2!, and is illustrated indetail inl 'igs. 3,4, and 5. Said bit comprises a flat front wall 21, the contour of which is asharp-ended ellipse; and two identical convex walls 28 and 29, the contours of which are segments of convex circular flames. The walls," and" merge into atransversely rounded narrow edge II which, in structural effect, is substantially a line and which is so designated in certain of the claims appended hereto; the walls 21 and 2! meet in a cutting curved-edge ii; and the walls 21 and 29 meet'in a cutting curved edge 22, identical with the edge 3!. .The edges ii and 22 meet, in the plane of the edge- 29, in a sharp cutting point '22 at one end, and in a sharp cutting point it at the other end.

The'shape o! the completed bit may, perhaps, be best described as the shape of a segment or a double convex disc. In this definition, the word eral diiferent ways; for instan by the method disclosed in my said co-pending application.

It will be readily seen that this bit element, normally not over 2 inches in length and approximately 1% of an inch in major width, provides an extremely inexpensive mining machine bit, double pointed, readily replaceable, and con taining so little material that it will be less expensive to replace it than to resharpen it. I

It willalso be seen, from the following disclosure, that in the present application I have illustrated one extremely eflicient, readily operable, holding means for such a bit; the advan-r 1 A tages of which, when used in connection with the illustrated bit, will be readily apparent to anyone familiar with the art to which the present invention pertains.

a clamping element, indicated generally by the.

reference numeral 35, for use with the bit of the present application, comprises a shank 38 receivable in the bore 22 and a head 3'i. Said clamping element 35 is formed in its forward face with a recess 38 substantially conforming to the shape of, and adapted snugly to receive, a portion of the curvedand convex walls of the bit 26. From a consideration-of Fig. 2, particularly, it will readily be seen-that, when a bit 28 is engaged in saidrecess 38, it will be snugly held with its surface 2'! in contact with the flat surface 26 of the bore 22. It will also be seen that, because of the particular shape of the bit:

with an inclined step ll! engageable by the end of a set screw 42 threadedly received in a bore 4i formed in the bit block; and it will be apparent, from a consideration of Fig. 2, that the set screw 52 tends, when turned. down against the step til, to urge the shank 36 inwardly of the bore 22.

Unavoidably. when a mining machine is used in a coal mine, fine coal dustflnds its way into i the sockets of the bit-carrying blocks. With devices of the prior art, it is not uncommon for the sockets to become so solidly packed with coal dust as to make it substantially, if not quite, impossible to remove the bit holding means disposed therein without actually drilling the metal away.

To overcome this dimculty, I provide a passage whereby coal dust, which finds its way into the socket 22, may find egress therefrom. The action of the mining machine is such that coal dust will be shaken out, through a passage of the type which I .have provided, during operation of the machine, so that it will never become packed in the socket.

As has been stated, the bore in which the shank 36 is received extends entirely through the bit block. In order further to facilitate egress of coal dust, however, I have provided the second bore 25 which leads downwardly from substantially the junction of the portions 22 and 23 of the primary bore, and opens through the downwardly-disposed wall of the bit block. In order further to facilitate the passage of coal dust through the block, however, I prefer to form the shank with a bore or passage 39 which leads from a point adjacent the base of the recess 38 through the base of the shank 36 and so into the bore 22. In practice, it is found that the coal dust passes straight through the organization of the pi pplication and does not pack in the holder socket.

Under extreme conditions, it is possible that, in spite of the provision of the safeguards above described, dirt might become packed in the block socket. Under such circumstances, it will be clear that the provision of the bore 25 adjacent the base of the shank 36 would make it possible for the operator to insert a tool through the bore 25 to engage the base of said shank 36 to pry the holder 35 out of the bore.

In use, the bit 28 is placed in recess 38 of clamping'element 35 and the two parts are inserted into the socket 22 with the face 27 of the bit resting on the surface 24 of the socket. Screw 42 is then forced down upon surface til of the holder 35, and the holder 35 is thereby urged inwardly, surface 21 of the bit sliding inwardly Q on surface 24 of the socket 22 until the clamping element and bit are firmly wedged into place. Because of this wedging action or screw 42 on element 35, the shank of the element 35 may loosely fit the bore 22 and the bore and shank need not be accurately machined. As a consetguence, any distortions of the shank and socket resulting from normal use do not interfere with ready removal and replacement of the clamping element and bit.

It will be noted that the inner tip of the bit Therefore any battering of the active tip of the bit, arising from normal use, will not interfere.

with reversal of the bit to bring the previously unused tip of the bit into active position.

It will also be noted that resistance offered by the work to passage of the bit tends to drive the bit inwardly along surface 24 o! the block 20 and concurrently to drive the element 35 inwardly into the block 29. thereby maintaining the bit firmly in place at all times so as to avoid all chatraring of the bit and element 85 in the block.

I claim as invention:

i. As a new article of manufacture, a cutter bit comprising a metal piece having the shape of a segment of a symmetrical double-convex disc.

2. As a new article of manufacture, a cutter bit formed with a continuous flat face terminating in cutting points at its opposite ends, said bit further being formed with two sides leading from the lateral edges of said flat face and merging in an arc of a circle.

3. The combination with a cutter bit. of a holder therefor comprising a block formed with opening from said recess into i stantially perpendicular to said screw axis and engageabie by said screw for shifting the tool post axially to wedge a front surface of the bit against sai abutment.

9. As a new article of manufacture. a cutter bit formed with a flat front face outlining an elongated ellipse donning a pair of opposite cutting ends, and a pair of identical side surfaces leading from the lateral edges of said ellipse and converging in a curving, blunted rear edge, conceive said portion and to hold a flat front surface of said bit against a flat surface provided on said block, said shank being formed with a dirt passage opening from said recess into said ter-bit formed socket, and said block being formed with a bore intersecting said socket and opening through that" wall of said block which, in theworking position ofsaid block. faces downwardly.

5. The combination with a cutter bit, of a m merging in an arc holder therefor comprising a block-formed with a a socket therein disposed, in the working position of the block, upon a substantially horizontal axis. a clamping element comprising a head and a shank, said shank being receivable in said socket, a recess formed in said head and conforming substantially to the contour of a portion of the-rear surface of said bit and adapted snugly to receive said portion and to hold 'a flat front surface of said bit against a flat surface provided on said generally to the contour of such abutment surface to midpoint when said, shank block, said shank being formed with a dirt passage opening from said recess through the base of said shank, and said block being formed with a bore intersecting said socket. adjacent the base of said shank and opening through that wall of said block which, in the working position of said block, faces downwardly.

s. The combination with a cutter bit, or a holder therefor comprising a block formed with V a socket, and a clamping element comprising a head and a shank, said shank being receivable in said socket, a recess formed in said head and conforming substantially to the contour of a portion of the rear surface only of, said bit and adapted snugly to receive said; portion and to hold a front surface of said bit against an abut ment surface provided on said block, said shank being formed with a dirt e opening from said recess into said socket.

7. A 'mining machine chain link having a socket, an immovable forwardly and outwardly inclined abutment upstanding from the linkand in front of the mouth of said /socket, a tool post with its inner end received in said socket and its outer end protruding therefrom and having an open-sided bit engaging seat formed on its front dds corresponding in contour with a rear surface only of a plural pointed bit carried therein and generally inclined inwardly and rearwardly and extending into said socket, and a threaded member engaging the forward surface of the innor end of the tool post for shifting it axially of said socket to wedge a front surface of said bit a ainst said abutment.

8. In a mining chain link, a socket, an immovable abutment upstanding from the link in front of said socket, a movable tool post in th socket and upstanding therefrom, a bit having a curvilinear back side engaged against a corresponding mounted in said link on an axis inclined to the axis of said socket and projectible into said socket and an abutment surface on said tool post sub- 40 from the lateral edges of melting in an are so less'at either end engagement with forming in the arc of a circle.

i0. In a miningrmachine chain, a bit block formed with a socket definin an outwardly inclined abutment surface, in combination, a cutwith a substantially continuous terminating in cutting points at with allochiral side surfaces leading respectively from the lateral edges of said front face and of a circle, and a brace for said bit including a shank receivable in the socket of such block and a head, said brace being formed to provide a seat having allochiral side walls merging in an arc of a circle and conforming a portion of the surfaces of said bit side surfaces intermediate said cutting points, th perpendicular distance from the arc of said seat said seat than at its is received in such socket, whereby said seat wedges the flat face of said bit againstsuch surface. i i

ll. In a mining machine a socket defining an outwardly inclined abutment surf ce, in combination, a, cutb ing less at either end of ter bit formed with a substantially continuous flat front face terminating in cutting points at its opposite ends, said bit further being formed with allochirai side surfaces leading respectively said front face and 'bit including a shank receivable in the socket of such block and a head, said brace being formed to provide a seat having allochiral side walls of a circle and conforming genur of a portion of the surface aces intermediate said cutting orally to the con of said bit side points, the perpendicular distance from such abutment surface to the arc of said seat being of said seat than at its midpoint when said shank i received inauch socket, whereby said seat wedges the flat face of said bit against such surface, and means carried by said block and shiftablewith respect thereto in said shank to effect such weds-- ing action.

12. In a mining machine chain. a. bit block formed with a socket and formed to provide a rearwardly and outwardly facing inclined surface anguiarly related to the axis of said socket, a bit seat conforming in contour with a portion having a cutting face terminating in oppositely directed cutting points and adapted to bear against said surface, and a holder'for said Mt having a shank receivable in said socket and having a head projecting from said socket, said bit being shaped with an arcuate edge lying in a 1 plane normal to its cutting face and including said points, and said holder being formed with a of said edge and embracing portions of the lateral walls of said bit, said seat extending an appreciable distance in both directions from the midpoint of said arcuate edge, whereby the perpendicular distance from said inclined surface to the said conends, said bit further being formed forming portion of said seat is less at either end of said seat than at said midpoint.

13. In a coal cutting mechanism, an organization comprising a socketed member, a small plural pointed cutting tooth, a tooth supporting post with its inner end extending into the socket of said member and its outer end projecting therefrom, said post having an open-sided bit-- ly of said socket upon the line of its longitudinal axis, together with an immovable forwardly and outwardly inclined wedging surface formed on said socketed member at the front of the mouth or said socket, overlying said screw and engaging in a wedge lock manner the front face of said bit coincidental with said inward thrust of said post.

14. For use in a mining machine, a bit holder formed with a shank and a. head, and further formed with a bit-receiving recess opening through the front face of said head, and with a hole in said shank intersecting said recess and opening through an' external surface of said shank.

shank and ahead, and being further formed with a recess opening through the front face of said head and generally inclined forwardly and outwardly, and with a hole in said shank intersecting said recess and opening through an external surface of said shank, said bit being received in said recess with an inactive point projecting into K said hole.

16. For use in a mining machine, a bit holder formed with a shank and a head, and further formed with a bit-receiving recess opening through a wall of said holder, and with a hole in said shank intersecting said recess and opening through the innerend, of said shank.

17. The combination with a. mining machine chain bit block having a socket therein, of a plural-pointed bit and a holder therefor, said holder being formed with a shank receivable in said socket, and with a head, said holder being further formed with a recess opening through the front face of said head and generally inclined forwardly and outwardly, and with ahole in said shank intersecting said recess and opening through an external surface-of said shank, a step formed on the forward surface of said shank and comprising an outwardly and rearwardly inclined plane, and a screw having a flatnose threadedly mounted in a bore in said block and flatly engageable with saidstep to urge said holder inwardiy of said socket, said step intersecting said -.hole and being disposed inwardly beyond the 15. In combination, a plural-pointed bit and a holder therefor, said holder being formed with a inner end of said recess. 

